Compact, low-cost and low-noise lasers are critical for the development of high performance analog photonics systems, such as fiber optic transmission systems. However, such lasers have not yet been satisfactorily developed.
For example, the use of externally-pumped solid state lasers to produce laser beams for fiber optic transmission is well-known. Such laser systems might include Er:Yb-doped glass microchip lasers, which are particularly useful for generating light beams having appropriate wavelengths for optical communications systems (i.e., 1530-1560 nm). However, such laser systems typically require the use of expensive or inefficient pumping mechanisms, such as flash lamps.
Diode lasers are known to be a relatively inexpensive and efficient pumping mechanism; however, such lasers are typically too low in power and beam quality to be effective in a wide range of applications. In particular, low-power vertical cavity surface emitting lasers (VCSELs), having a power output of approximately 2-5 mW, are known to be inexpensive and easy to produce. Moreover, VCSELs are well-suited for certain fiber optic applications, e.g., low-power transmissions over multimode fibers, due to the ease of matching the light emitted from the circular emitting facet of a VCSEL to a similarly-shaped core of a fiber optic cable.
However, conventional VCSELS, like edge-emitting diode lasers, are too low in power to effectively serve as a pumping mechanism for a doped-glass laser such as the Er:Yb laser referred to above. Moreover, output power of a single VCSEL cannot be increased effectively by increasing the size of the surface area of its emitting facet, due to poor heat dissipation properties of such a VCSEL. It is known to overcome this shortcoming by arranging multiple VCSELs into an array and including a heat sink attached to the device side of these VCSELs (as opposed to the substrate side). However, such high-power arrays of VCSELS were contemplated only in the context of optical ignition mechanisms. Finally, conventional laser systems including VCSEL devices typically require extensive use of external, discrete lens systems for effective utilization of the VCSEL output beams. The need to include and arrange such lens systems is responsible for an increase in system size and cost.